1. Field of the Invention
The present invention relates to a method of producing a semiconductor device of a wafer level chip size package type, in which a semiconductor wafer with a plurality of semiconductor elements formed thereon is cut in pieces to obtain the semiconductor device.
2. Description of Related Art
An electric device has been developed to have various functionalities processed at a higher speed in a smaller size. With this trend, it has been required to mount electrical elements on a conductive pattern substrate with a higher density. As a result of the high density, radio interference has become an issue between pins of a semiconductor device or relative to a peripheral device and other semiconductor device.
The radio interference is mainly caused by a radiation noise generated from an active circuit of a semiconductor element. The radiation noise is generated from a conductive pattern on a mount substrate or a surface of a semiconductor device such as a front surface, a rear surface, or a side surface, thereby causing the radio interference such as radio disturbance and abnormal resonance.
In order to reduce the radio interference, a conventional semiconductor device is provided with a cap formed of a radio wave suppression member having a conductive layer in a front surface or inside for covering the semiconductor device (refers to Patent Reference 1).    Patent Reference 1: Japanese Patent Publication (Kokai) No. 2002-16167
In the conventional semiconductor device, the cap formed of the radio wave suppression member is attached to the semiconductor device after the semiconductor device is produced. Accordingly, it is necessary to attach the cap in an additional step after the semiconductor device is produced, thereby increasing production time and lowering production efficiency of the semiconductor device. Further, when the semiconductor device is provided with the radio wave suppression function after the semiconductor device is produced, the semiconductor device has a size larger than that of a semiconductor element (chip size). Accordingly, it is difficult to reduce a chip size to meet the requirement for the high density mounting.
In view of the problems described above, an object of the present invention is to provide a semiconductor device with the radio wave suppression function having a size substantially same as a chip size. Another object of the present invention is to provide a method of efficiently producing the semiconductor device.
Further objects and advantages of the invention will be apparent from the following description of the invention.